JP5499627B2 - Heat exchange element and heat exchange method - Google Patents

Description

  The present invention relates to a heat exchange element and a heat exchange method for performing heat exchange across a flow path wall of a mixed fluid of a heat exchange medium and a functional fluid.

  In an air conditioner cycle, a technique of mixing oil for lubricating a compressor with a refrigerant is known (for example, see Non-Patent Document 1). Further, a refrigeration cycle in which an oil repellent film is formed on the inner wall surface of a refrigerant channel is known (see, for example, Patent Document 1).

Ozaki et al., “Oil circulation rate measurement in CO2 air conditioner cycle”, Denso Technical Review, Vol. 8 No. 2, 2003

JP-A-9-210513

  However, in the former prior art described above, in order to suppress heat exchange loss due to lubricating oil, measures such as providing an oil separator that separates oil from refrigerant during the air conditioner cycle are required. There is room for improvement in terms of mass. On the other hand, the latter technique also has room for improvement from the viewpoint of suppressing heat exchange loss, that is, improving the heat transfer coefficient.

  An object of the present invention is to obtain a heat exchange element and a heat exchange method capable of suppressing heat exchange loss while using a heat exchange medium mixed with a functional fluid.

The heat exchange element according to the invention of claim 1 is a flow path of a mixed fluid of a fluorine-based refrigerant as a heat exchange medium and a lubricating oil containing mineral oil as a functional fluid incompatible with the heat exchange medium. The surface of the flow path wall to be formed has a fine uneven structure, and the surface has a high affinity with the fluorinated refrigerant and is subjected to a fluorine treatment that is a water repellent treatment . A heat exchange medium is selectively attached to the surface.

  In the heat exchange element according to claim 1, since the surface of the flow path wall is subjected to a surface treatment having high affinity with the heat exchange medium, the surface of the flow path wall has heat among the components of the mixed fluid. An exchange medium is selectively deposited. Thereby, in this heat exchange element, heat is applied to the functional fluid and the object on the back side of the channel wall (fluid or solid contacting the back side, the cooling or heating object integrally formed on the back side of the channel wall). Good heat exchange is performed with a heat exchange medium having a high transfer rate. Moreover, since the surface of the flow path wall has a fine uneven structure, the heat transfer coefficient between the heat exchange medium selectively attached to the surface and the object on the back side of the flow path wall is improved. A better heat exchange is performed between them.

  Thus, in the heat exchange element according to claim 1, heat exchange loss can be suppressed while using the heat exchange medium in which the functional fluid is mixed.

  A heat exchange element according to a second aspect of the present invention is the heat exchange element according to the first aspect, wherein the functional fluid is used as a lubricating oil and is applied to a heat exchanger of a refrigeration cycle.

In the heat exchange element according to the second aspect, the functional fluid contributes to lubrication of, for example, a compressor constituting the refrigeration cycle. On the other hand, the heat exchange medium contributes to ensuring the performance of a refrigeration cycle in which good heat exchange is performed by an evaporator or a condenser, and lubricating oil is mixed as a functional fluid with the heat exchange medium .

According to a third aspect of the present invention, there is provided a heat exchange method comprising: a flow path of a mixed fluid of a fluorine-based refrigerant as a heat exchange medium and a lubricating oil containing mineral oil as a functional fluid incompatible with the heat exchange medium. As a surface treatment having a high affinity with the heat exchange medium, a flow treatment having a high affinity with the fluorinated refrigerant and a water repellent treatment is applied to the flow path wall surface having a fine uneven structure to be formed. While selectively adhering the heat exchange medium to the surface of the road wall, heat exchange between the heat exchange medium and the object on the back side of the flow path wall is performed.

In the heat exchange method according to claim 3, while using a flow path wall having a surface treated with a surface having high affinity for the heat exchange medium, the heat exchange medium is selectively attached to the surface of the flow path wall. Then, heat exchange is performed between the heat exchange medium and the object on the back surface side of the flow path wall (fluid or solid contacting the back surface, or a cooling or heating object integrally formed on the back surface side of the flow path wall). For this reason, in this heat exchange method, favorable heat exchange is performed between the object on the back side of the flow path wall and the heat exchange medium having a high heat transfer coefficient with respect to the functional fluid. In addition, since the surface of the flow path wall has a fine uneven structure, the heat transfer coefficient between the heat exchange medium selectively attached to the surface and the object on the back side of the flow path wall is improved. Better heat exchange between them.

Thus, in the heat exchange method according to the third aspect , the heat exchange loss can be suppressed while using the heat exchange medium in which the functional fluid is mixed .

  As described above, the heat exchange element and the heat exchange method according to the present invention have an excellent effect that heat exchange loss can be suppressed while using a heat exchange medium in which a functional fluid is mixed.

It is a sectional side view which shows typically schematic structure of the heat exchange element which concerns on embodiment of this invention. It is a diagram which shows the heat conductivity characteristic of the refrigerant | coolant and lubricating oil in the mixed fluid which flows through the heat exchange element which concerns on embodiment of this invention. It is a diagram which shows the experimental result for demonstrating the selective adhesion of the refrigerant | coolant by the heat exchange element which concerns on this embodiment, comparing with a comparative example. It is a figure which shows notionally the structure of the apparatus for an experiment which shows the experimental result of FIG. 3, Comprising: (A) is sectional drawing, (B) is a front view. It is a diagram which shows the experimental result for demonstrating the improvement effect of the heat transfer rate by the heat exchange element which concerns on this embodiment. It is a figure which shows notionally the structure of the apparatus for experiment which shows the experimental result of FIG. It is a diagram which shows the experimental result for demonstrating the boiling characteristic by the heat exchange element which concerns on this embodiment. It is a figure which shows notionally the structure of the apparatus for an experiment which shows the experimental result of FIG. It is a block diagram which shows the car air conditioner to which the heat exchange element which concerns on this embodiment was applied.

  The heat exchange element 10 which concerns on embodiment of this invention is demonstrated based on drawing. FIG. 1 shows a schematic overall configuration of the heat exchange element 10 in a cross-sectional view along the flow direction of the mixed fluid 12 (see arrow F). Supplementing the mixed fluid 12, the mixed fluid 12 is a mixture of a refrigerant 14 as a heat exchange medium and lubricating oil (oil) 16 as a functional fluid. The refrigerant 14 and the lubricating oil 16 are incompatible with each other (insoluble) and do not melt together (can be mechanically separated and an interface is formed in the separated state). In this embodiment, a fluorine-based refrigerant is used as the refrigerant 14, and mineral oil (with additives appropriately added thereto) is used as the lubricating oil.

  The heat exchange element 10 includes a flow path wall 20 that forms the flow path 22 of the mixed fluid 12 and the flow path 24 of the counterpart fluid 18 that exchanges heat with the refrigerant 14 of the mixed fluid 12. The channel wall 20 can be regarded as a partition wall between the channel 22 of the mixed fluid 12 and the channel 24 of the counterpart fluid 18. In the following description, the surface on the flow channel 22 side of the mixed fluid 12 in the flow channel wall 20 is referred to as the front surface 20A, and the surface on the flow channel 24 side of the counterpart fluid 18 is referred to as the back surface 20B.

  On the surface 20 </ b> A of the flow path wall 20, a sub-micron-order fine uneven structure 26 is formed. The fine concavo-convex structure 26 in this embodiment has a pitch P (in FIG. 1, it is the distance between the lowest portions of the adjacent concave portions 26A, but may be regarded as the distance between the peaks of the adjacent convex portions 26B), When the depth (depth from the peak of the convex portion 26B to the lowest portion of the concave portion 26A) is D, D> P. In this embodiment, P≈1.5 μm and D≈40 μm (D >> P). Thereby, a part of the mixed fluid 12 (the refrigerant 14 as described later) can be held in the concave portion 26 </ b> A that opens to the flow path 22 side in the fine uneven structure 26. In addition, this fine uneven structure 26 can be formed by methods, such as an etching, plating, an oxide film, and peening, for example. The pitch P is preferably set within a range of 0.1 μm to 10 μm. Moreover, it is preferable to set the depth D within the range of 10-50 micrometers.

  In the heat exchange element 10, the surface treatment 28 having high affinity with the refrigerant 14 is applied to the fine uneven structure 26 (the surface 20 </ b> A of the flow path wall 20). The surface treatment 28 is performed following the surface of the fine uneven structure 26 (so as not to fill the recess 26A). Thereby, the affinity with respect to the refrigerant | coolant 14 is improving the surface 20A of the fine uneven structure 26, ie, the surface 20A of the flow-path wall 20. FIG.

  In the present embodiment in which a fluorine-based inert liquid is applied as the refrigerant 14 as described above, the surface treatment 28 may be regarded as, for example, fluorine treatment for forming a fluorine coating (water repellent treatment for forming a multimolecular thin film). ) Can be adopted. More specifically, in this embodiment (an experimental example to be described later), Fluorinert FC-84 manufactured by Sumitomo 3M Co. as the refrigerant 14 is used as the surface treatment 28, and a fluorine-based surface treatment manufactured by Sumitomo 3M Co., Ltd. is used. Agent EGC-1720) is employed.

  If the flow field FF of the mixed fluid 12 in the flow path 22 is supplemented, the flow field FF is a shear flow field whose shear rate increases as the flow field FF is separated from the flow path wall 20 in a direction orthogonal to the flow direction. Yes. This shear flow field FF includes a shear flow field due to relative displacement such as straight and rotation of a pair of flow path walls, and pressure flow (Poiseuille flow) between parallel plates and pipes (regardless of cross-sectional shape). It is.

  Next, the operation of this embodiment will be described.

  In the heat exchange element 10 having the above configuration, the surface treatment 28 having high affinity with the refrigerant 14 is applied to the surface 20 </ b> A of the mixed fluid 12 in the flow path wall 20, so that the refrigerant out of the mixed fluid 12 flowing through the flow path 22. 14 is selectively attached to the surface 20 A of the flow path wall 20. Thereby, in the heat exchange element 10, since the other party fluid 18 and the refrigerant | coolant 14 perform heat exchange via the flow-path wall 20, there are few heat exchange losses.

  That is, as shown in FIG. 2, when the refrigerant 14 and the lubricating oil 16 are compared, the refrigerant 14 has a higher heat transfer coefficient than the lubricating oil 16 at each flow rate, so the refrigerant 14 is selected as the surface 20A of the flow path wall 20. Therefore, the heat exchange loss is reduced as compared with the case where the mixed fluid 12 is directly attached to the surface 20A of the flow path wall 20 or only the lubricating oil 16 is attached. That is, the heat exchange performance is improved. Further, in the cooling application of the counterpart fluid 18, the refrigerant 14 attached to the surface 20A of the flow path wall 20 and held in the recess 26A is likely to boil (evaporate), so that a cooling effect due to the boiling of the refrigerant 14 can also be expected. . In particular, since the fine uneven structure 26 is formed on the surface 20A of the flow path wall 20, the heat transfer rate is improved and the refrigerant 14 is easily boiled, so that the heat exchange performance and the boiling cooling performance are improved ( This point will be supplemented later).

  The point where the refrigerant 14 selectively adheres to the surface 20A of the flow path wall 20 will be described with reference to the experimental results of FIGS. FIG. 3 shows the experimental results showing the change over time of the adhesion of the lubricating oil 16 to the surface 20A of the flow path wall 20 performed using the apparatus shown in FIG. The experimental apparatus 30 shown in FIG. 4 provides a rotating disk 32 in a short cylindrical transparent container 34 so that it can rotate simultaneously and relatively, and observes the lubricating oil 16 adhering to the surface of the rotating disk 32. . The rotating disk 32 is made of aluminum, and as a surface state thereof, the embodiment model 32A in which the fine uneven structure 26 and the surface treatment 28 are applied corresponding to the flow path wall 20, and the surface treatment 28 is provided on the flat surface of the aluminum surface. Four types are prepared: a first comparative example model 32B, a second comparative example model 32C that employs only the fine uneven structure 26 on the aluminum surface, and a third comparative example model 32D that is simply a flat surface of the aluminum surface. did.

  Then, in the transparent container 34, the refrigerant 14 (substantially transparent) and the mixed fluid 12 of the lubricating oil 16 (colored) 12 (in the stationary state as shown in FIGS. 4A and 4B), the refrigerant 14 and the lubricating oil 16 are mixed. A graph plotting the time variation of the adhesion area of the lubricating oil 16 to the surface of the rotating disk 32 observed while rotating the rotating disk 32. It is an experimental result of FIG.

  From the results of FIG. 3, it can be seen that in the second and third comparative examples, the lubricating oil 16 continues to adhere to almost the entire surface of the rotating disk 32 regardless of the passage of time. On the other hand, in the embodiment model and the first comparative example model, the adhesion area of the lubricating oil 16 to the surface of the rotating disk 32 is reduced with time, and finally, the adhesion area is reduced to a level that can be almost ignored. I understand that In other words, according to this experimental result, in the second and third comparative examples, the lubricating oil 16 (including the mixed fluid 12) is attached to the surface of the rotating disk 32, whereas the embodiment model and the first comparison In the example model, it was confirmed that the refrigerant 14 selectively adheres to the surface of the rotating disk 32 in a steady flow excluding the initial stage of rotation.

  In the second and third comparative examples, the lubricating oil 16 is attached to the surface of the flow path wall, so that the heat exchange loss is relatively large. In the heat exchange element 10, as described above, the flow path wall Since the refrigerant 14 is selectively attached to the surface 20A of the 20, the heat exchange loss is small and good heat exchange performance is obtained.

  Next, it supplements about the point which cooling performance improves by the fine uneven structure 26, the point to which a heat transfer rate improves more specifically, and the point where a boiling of a refrigerant | coolant becomes easy to produce. First, the former will be described with reference to FIGS. 5 and 6, and then the latter will be described with reference to FIGS. 7 and 8.

  FIG. 5 shows the measurement results of the heat transfer coefficient of the test piece of the example model corresponding to the flow path wall 20 and the test piece of the comparative example obtained by the forced convection test using the apparatus shown in FIG. ing. In the apparatus shown in FIG. 6, an air flow is brought into contact with the test piece 52 while the test piece 52 is heated by the test piece heating device 50, and the temperature Tw, the heat flux q, and the test piece 52 of the test piece 52 are brought into contact. The temperature Ta of the previous air flow is measured. The test piece heating device 50 includes a copper cylinder 54, a heater 56 that heats the copper cylinder 54, and a heat insulating material 58 that covers the copper cylinder 54 and the heater 56, and a test piece 52 that is in contact with one end of the copper cylinder 54. Only the heating is selectively (directly) performed. A sensor 60 in which a thermocouple and a heat flux sensor for measuring the temperature Tw and the heat flux q are integrated is provided between the copper cylinder 54 and the test piece 52. The temperature Ta is measured by a thermocouple 62. In addition, the test piece 52 is made of aluminum, and the surface state of the test piece 52 is an embodiment model 52A provided with the fine uneven structure 26 corresponding to the flow path wall 20, and a comparative example model 52B which is a flat surface of the aluminum surface. Prepared.

And using temperature Tw, heat flux q, and temperature Ta measured with this device,
Heat transfer coefficient α = q / (Tw−Ta)
Calculate the heat transfer coefficient. FIG. 5 is a plot of the calculated heat transfer coefficient against the wind speed of the forced air flow. The measurement conditions in FIG. 5 are such that the wind speed is 2 m / s to 8 m / s, and the amount of heat input by the heater 56 is 8.4 W (= 0.28 A × 30 V).

  From FIG. 5, in the embodiment of the present embodiment in which the fine uneven structure 26 is formed, the heat transfer coefficient is improved by a little over 10% at each wind speed of the air flow as compared with the comparative example which is a flat surface without the fine uneven structure 26. It was confirmed that Thereby, the heat exchange performance between the refrigerant 14 (liquid having a relatively high heat transfer coefficient in the mixed fluid 12) and the counterpart fluid 18 that are selectively brought into contact with the surface 20A of the flow path wall 20 by the surface treatment 28 is improved. To do. That is, the heat exchanging element 10 has higher heat exchanging performance as compared with the heat exchanging element 10 having a flow path wall with a flat surface to which the refrigerant 14 is selectively attached as in the first comparative example of FIG. In addition, the surface treatment 28 having a high affinity with the refrigerant 14 can selectively hold (trap) the refrigerant 14 in the concave portion 26A of the fine uneven structure 26, that is, the surface 20A of the flow channel wall 20, so that the flow channel wall A film of the refrigerant 14 can always be formed on the surface 20A of the 20 during the period in which the flow is generated, and this also contributes to the improvement of the heat exchange performance.

  Further, FIG. 7 shows experimental results of the test piece 52A of the embodiment model and the test piece 52B of the comparative example model obtained by the boiling characteristic test using the apparatus shown in FIG. The apparatus shown in FIG. 8 immerses the test piece 52 in the volatile liquid Fv in the container 64 while heating the test piece 52 with the test piece heating apparatus 50, and observes the state of boiling (bubble B). The heat flow rate is measured by the sensor 60. In order to facilitate the test, Fluorinert FC-72 manufactured by Sumitomo 3M Co., Ltd., which is a refrigerant having a boiling point lower than that of the refrigerant 14 (approximately 40 ° C.), was used as the volatile liquid Fv. The amount of heat input by the heater 56 was 24.5 W (= 0.49 A × 50 V). Furthermore, the test with each test piece 52 is performed with the test piece 52 temperature Tw = 28.1 ° C. ± 0.2 ° C. and the volatile liquid Fv temperature Tf = 22.5 ° C. ± 0.5 ° C. The heater 56 was activated 30 seconds after the start of measurement.

  When the test piece 52B according to the comparative example was used, boiling started after the time tbc (≈460 s) shown in FIG. At this time, bubbles were generated only from a limited portion of the test piece 52B. On the other hand, when the test piece 52A of the embodiment model was used, boiling started after the time tb (≈190 s) shown in FIG. At this time, it was observed that bubbles were actively generated in each part of the test piece 52A. Thereby, in the form of this embodiment in which the fine uneven structure 26 is formed, it is easy to cause boiling of the liquid in contact with the comparative example which is a flat surface without the fine uneven structure 26 (required time until boiling is disclosed). , And the amount of evaporation per input energy is large). Further, as shown in FIG. 7, it was confirmed that in the test piece 52A, the heat flux in the state where the volatile liquid Fv was boiled with respect to the test piece 52B was large. As described above, in the heat exchange element 10, when applied to the cooling of the counterpart fluid 18 by latent heat, the counterpart fluid 18 due to the boiling of the refrigerant 14 that is selectively brought into contact with the surface 20 </ b> A of the flow path wall 20 by the surface treatment 28. High cooling effect (boiling cooling performance).

  In the heat exchange element 10, since the refrigerant 14 is held in the fine uneven structure 26 by the surface treatment 28 having a high affinity with the refrigerant 14, the main flow (outside the fine uneven structure 26 outside the fine uneven structure 26) flows through the flow path 22 of the mixed fluid 12. The flow) forms a broken flow field FF while contacting the refrigerant 14 instead of the solid wall. For this reason, in the heat exchange element 10, the flow resistance of the mixed fluid 12 can be reduced.

  Next, an application example of the heat exchange element 10 will be described.

  FIG. 9 is a schematic block diagram showing the car air conditioner 36 to which the heat exchange element 10 is applied. As shown in this figure, the car air conditioner 36 includes a compressor 38 as a compressor, a condenser 40 as a condenser, a gas-liquid separator 42, an expansion valve 44, an evaporator 46 as an evaporator, And an air conditioner refrigerant circulation path 48 communicating in series.

  The car air conditioner 36 has a configuration in which an air conditioner cycle that is a compression / expansion refrigeration (heat pump) cycle is executed by circulating air conditioner refrigerant in the order of the compressor 38, the condenser 40, the expansion valve 44, and the evaporator 46. Has been. Specifically, the air-conditioner refrigerant is compressed by the compressor 38 into a high-pressure gas phase, condensed by the condenser 40 to be a high-pressure liquid phase, expanded by the expansion valve 44 to be a low-pressure liquid phase, and then air-conditioned by the evaporator 46. The evaporator 46 is configured to cool the air-conditioning air by repeating an air-conditioning cycle that is made into a low-pressure gas phase by being evaporated by heat exchange with the working air.

  That is, the evaporator 46 is a heat exchanger between the air-conditioning refrigerant and the air-conditioning air, and cools the air-conditioning air by taking the latent heat of evaporation of the air-conditioning refrigerant from the air-conditioning air (outdoor air or indoor air). It is configured. The condenser 40 is a heat exchanger between the outside air and the air conditioner refrigerant, and is configured to release the heat of condensation of the air conditioner refrigerant into the airflow generated by the operation of the vehicle running wind or a fan (not shown).

  In the car air conditioner 36 to which the heat exchange element 10 according to this embodiment is applied, the refrigerant 14 that is a fluorine-based refrigerant is used as the air conditioner refrigerant, and the mixed fluid 12 is circulated through the air conditioner refrigerant circulation path 48. Has been. As a result, the above-described air-conditioner cycle is executed by the refrigerant 14 in the mixed fluid 12, and the compressor 38 is lubricated by the lubricating oil 16 in the mixed fluid 12.

  Here, in the car air conditioner 36, the heat exchange element 10 is applied to the evaporator 46. Specifically, the evaporator 46 is configured by using the flow path wall 20 as a partition wall between the flow path of the air conditioner refrigerant and the flow path of the air conditioning air. The flow path wall 20 is provided with the front surface 20A facing the flow path side of the air conditioner refrigerant and the back surface 20B facing the flow path side of the air conditioning air.

  As a result, the mixed fluid 12 flowing through the flow path of the air-conditioner refrigerant (the flow path 22 of the mixed fluid 12) in the evaporator 46 is selectively attached to the surface 20A of the flow path wall 20 with the refrigerant 14 and the air-conditioning Heat exchange with the working air is satisfactorily performed, and the refrigerant 14 is evaporated by removing the latent heat of evaporation from the air for air conditioning, and the conditioned air deprived of the latent heat of evaporation is cooled.

  For example, in a car air conditioner according to a comparative example including an evaporator to which the heat exchange element 10 is not applied, the lubricating oil 16 of the mixed fluid 12 flows on the flow path wall side, and the heat exchange loss of the evaporator may increase. Are known. As a countermeasure, in the car air conditioner according to the comparative example, for example, an oil separator is provided on the discharge side of the compressor 38, and the lubricating oil 16 separated by the oil separator is returned to the suction side of the compressor 38. . For this reason, in the car air conditioner according to the comparative example, the number of parts is large and the mass tends to increase.

  On the other hand, in the car air conditioner 36 to which the heat exchange element 10 is applied, as described above, the refrigerant 14 in the mixed fluid 12 is selectively attached to the surface 20A of the flow path wall 20 to reduce heat exchange loss. Therefore, in the configuration in which the mixed fluid 12 is circulated through the air conditioner refrigerant circulation path 48, the required air conditioner performance can be ensured. In addition, since the fine uneven structure 26 is formed on the surface 20A of the flow path wall 20, the heat transfer performance and the boiling cooling performance are improved. Therefore, the air conditioner performance using the evaporator 46 which is a latent heat cooler (air conditioning air Cooling performance) is further improved. For this reason, the car air conditioner 36 can eliminate the need for an oil separator, and can reduce the number of parts and reduce the weight (the weight of the applied automobile as a whole).

  Moreover, since the heat exchange element 10 has the flow resistance reduction effect as described above, it contributes to the pressure loss reduction of the car air conditioner 36. In particular, the configuration in which the compressor 38 is driven by an automobile drive source (such as an engine) contributes to improvement in fuel consumption.

  In the application example described above, the heat exchange element 10 is applied to the evaporator 46. However, the present invention is not limited to this. For example, the heat exchange element 10 may be applied to the condenser 40. .

  In the application example described above, the heat exchange element 10 is applied to the heat exchanger of the car air conditioner 36 (refrigeration cycle). However, the present invention is not limited to this, and the heat exchange element 10 The present invention can be applied to various types of heat exchange elements (heat exchanger components, etc.), elements to be cooled, elements to be heated and the like through which a mixed fluid of an exchange medium and a functional fluid flows. Examples of the element to be cooled to which the heat exchange element 10 can be applied include various gearboxes including transmissions that require cooling and lubrication, industrial machines, etc. (lubricating oil circulation portion thereof), and heat sinks. That is, the heat exchange target of the refrigerant 14 is not limited to the fluid that contacts the back surface 20B of the flow path wall 20, and solids that contact the back surface 20B, structural components of the machine in which the flow path wall 20 is integrated, and the like. Can be subject to heat exchange. Further, the function of the functional fluid is not limited to lubrication, and for example, it is possible to adopt a configuration that fulfills the function of transporting the refrigerant to the heat exchange element (securing the flow rate).

Furthermore, in the above embodiment, a fluorine-based refrigerant as a refrigerant 14, a fluorine-based surface treatment is an example which has been subjected as a higher affinity surface treatment 28 with respect to the fluorine-based refrigerant, as a reference example, for example, It is good also as a structure which uses a silicon-type refrigerant | coolant as the refrigerant | coolant 14, and performs a silica process as a surface treatment with high affinity with respect to this silicon-type refrigerant | coolant.

10 Heat Exchange Element 12 Mixed Fluid 14 Refrigerant (Heat Exchange Medium)
16 Lubricating oil (functional fluid)
20 Channel wall 20A Surface 26 Fine uneven structure (uneven structure)
28 Surface treatment 36 Car air conditioner (refrigeration cycle)
46 Evaporator (Heat Exchanger)

Claims (3)

The surface of the flow path wall forming the flow path of the mixed fluid of the fluorine-based refrigerant as the heat exchange medium and the lubricating oil containing mineral oil as the incompatible functional fluid with the heat exchange medium has a fine uneven structure. At the same time, the surface is subjected to fluorine treatment that has high affinity with the fluorine-based refrigerant and is water repellent so that a heat exchange medium is selectively attached to the surface of the flow path wall. Heat exchange element configured to. Heat exchange elements of the applied claim 1, wherein the heat exchanger of refrigeration cycle. On the flow path wall surface having a fine uneven structure that forms a flow path of a mixed fluid of a fluorine-based refrigerant as a heat exchange medium and a lubricating oil containing mineral oil as an incompatible functional fluid with the heat exchange medium, Fluorine treatment having high affinity with the fluorinated refrigerant and water repellency treatment is performed, and the heat exchange medium and the flow path wall are selectively adhered to the surface of the flow path wall. A heat exchange method for exchanging heat with an object on the back side.

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